Electric concrete cutter

Abstract

To provide an electric concrete cutter capable of self-traveling even when an external power source is not supplied.SOLUTION: A cutter vehicle 10 comprises a cutter blade 22, an electric motor 24 for driving the cutter blade 22, a vehicle body 12 that houses the cutter blade 22 and the electric motor 24, a plurality of front wheels 14 and rear wheels 16 that rotatably support the vehicle body 12, and a power transmission device 26 that transmits output of the electric motor 24 to the plurality of rear wheels 16 serving as driving wheels. The electric motor 24 can be operated by either power supplied from an external power source, which serves as first power supply means, through a connector 28, or power supplied from a battery 34, which serves as second power supply means different from the first power supply means. Thus, the electric motor 24 can be operated by power supplied from any of a plurality of different power supply means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electric concrete cutter, and more particularly to an electric concrete cutter that can selectively use a plurality of power supply means. [Background technology]

[0002] Concrete cutters that cut road pavement surfaces and concrete surfaces are known. In such concrete cutters, a power unit rotates the cutter blade while the cutter itself travels, thereby performing cutting. For example, a concrete cutter is described in Patent Document 1. Patent Document 1 discloses a concrete cutter in which the cutting blade is driven by an engine and the cutter has a generator driven by the engine, and the wheels for propelling the concrete cutter are driven by a DC motor with a reducer that operates with voltage generated by the generator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-140817 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when cutting work is performed indoors or underground, exhaust gases emitted by the engine can be a problem, requiring concentration control and the installation of ventilation equipment, which can reduce work efficiency. To address this issue, it is possible to rotate the cutter blade using an electric motor. In this case, the electric motor must be supplied with power from an external source to provide the cutter blade with the torque and / or rotation speed required for cutting, just as in the case of engine-driven operation. In such cases, if no external power supply is available, the concrete cutter must be moved manually.

[0005] The present invention was made against the background of the above circumstances, and its purpose is to provide an electric concrete cutter that can be easily moved even when there is no external power supply. [Means for solving the problem]

[0006] The gist of the first invention is that (a) an electric concrete cutter having a cutter blade, an electric motor for driving the cutter blade, a body that houses the cutter blade and the electric motor, a plurality of wheels that rotatably support the body, and a power transmission device that transmits the output of the electric motor to some of the plurality of wheels, characterized in that (b) the electric motor is operable by either power supplied from a first power supply means or power supplied from a second power supply means different from the first power supply means. [Effects of the Invention]

[0007] According to the electric concrete cutter of the present invention, the electric motor that drives the cutter blade and supplies power to the power transmission device can be operated by any of the power supplied from a plurality of different power supply means.

[0008] The gist of the second invention is that in the electric concrete cutter of the first invention, the second power supply means is a battery, which allows the second power supply means to be contained within the electric concrete cutter.

[0009] The gist of the third invention is that in the electric concrete cutter of the second invention, the first power supply means is an external power source, and when power is not being supplied by the first power supply means, the electric motor is driven by power from the second power supply means, thereby allowing the external power source as the first power supply means to be used preferentially over the battery as the second power supply means.

[0010] The gist of the fourth invention is that in the electric concrete cutter of the third invention, the second power supply means drives the electric motor when cutting by the cutter blade is not being performed, so that the electric motor is driven by the battery, which is the second power supply means, when the load on the electric motor is small. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing a schematic configuration of an electric concrete cutter according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are schematic diagrams that have been appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0013] FIG. 1 is a side view of an electric concrete cutter (hereinafter also referred to as a cutter vehicle) 10 according to one embodiment of the present invention, showing the inside of the cutter vehicle 10 with the side cut away along the direction of travel.

[0014] The cutter vehicle 10 has a pair of rear wheels 16 and a pair of front wheels 14, one on the left and one on the right. Of these, the rear wheels 16 are drive wheels, and a driving force is supplied to the axles of the rear wheels 16 (not shown) from a power transmission device 26 (described later), allowing the cutter vehicle 10 to move in the front-to-rear direction. As will be described later, the power transmission device 26 has a differential function, which allows the left and right rear wheels 16 to rotate at different speeds, allowing the cutter vehicle 10 to turn left and right and move (travel).

[0015] The front wheels 14 are connected to the vehicle body 12 via lifting arms 18. The lifting arms 18 are capable of changing their angle relative to the vehicle body 12 by a power device, not shown, such as a hydraulic cylinder. This changes the amount by which the front wheels 14 protrude from the vehicle body 12. At this time, a line tangent to both the front wheels 14 and the rear wheels 16 forms the ground surface (the shaded area in FIG. 1 ). If a cutter blade 22 is attached to a tool rotation shaft 20 (described later), the amount by which the cutter blade 22 protrudes from the tangent line, in other words, the cutting depth into the ground, can be adjusted.

[0016] The tool rotation shaft 20 is a shaft for attaching the cutter blade 22, and is rotated by the driving force of a motor 24 (described later). The cutter blade 22 is connected to the tool rotation shaft 20 by, for example, a bolt, and rotates integrally therewith. When the cutter blade 22 is not attached, the tool rotation shaft 20 rotates idly. The cutter blade 22 is detachable, and when detached, the lifting arm 18 can be folded to its fullest extent, i.e., the front wheel 14 can be moved to a state where it protrudes the least. Figure 1 shows this state.

[0017] The cutter blade 22 has a disk shape and has cutting edges, for example, industrial diamonds fixed to its outer periphery. It also has, for example, a plurality of holes in its center for fastening to the tool rotation shaft 20, and is fixed so as to rotate integrally with the tool rotation shaft 20. Various types of cutter blades 22 are available, and an appropriate one is selected depending on the workpiece material, such as concrete or asphalt. Note that FIG. 1 shows the cutter blade 22 in a detached state, and the position of the cutter blade 22 when attached in this state is indicated by a dashed line.

[0018] The motor 24 generates power to be transmitted to the tool rotation shaft 20 described above and the power transmission device 26 described below. In this embodiment, an electric motor such as an induction motor that is driven by a three-phase alternating current is used. The motor 24 and the tool rotation shaft 20 may be connected, for example, by pulleys provided on the output shaft of the motor 24 and the tool rotation shaft 20, with a belt wound between the pulleys, so that the tool rotation shaft 20 rotates at a desired speed via the belt. Alternatively, gears may be provided on the output shaft of the motor 24 and the tool rotation shaft 20, and the gears may be meshed to transmit power.

[0019] In this embodiment, the power transmission device 26 is a hydraulic continuously variable transmission, specifically, a hydraulic static transmission (HST). This HST transmits power by differential oil flow between a variable displacement hydraulic pump and a hydraulic motor. By changing the displacement of the variable displacement hydraulic pump, the rotation direction of the output shaft relative to the input shaft of the power transmission device 26 can be switched between forward and reverse. In other words, the cutter vehicle 10 can be driven forward or backward. Furthermore, because the displacement of the variable displacement hydraulic pump can be changed continuously, the gear ratio of the power transmission device 26 can also be changed continuously. Furthermore, because differential oil can be prevented from being supplied from the variable displacement hydraulic pump, the power transmission device 26 can be placed in a neutral state, in which power transmission between the input shaft and the output shaft is interrupted.

[0020] In this embodiment, the power transmission device 26 also has a differential function, which allows the pair of left and right rear wheels 16 to be driven while allowing for a difference in rotational speed when power is transmitted from the power transmission device 26 to the drive shafts of the rear wheels 16.

[0021] Although not shown in the figures, the cutter vehicle 10 of this embodiment has an operation panel that allows the operator to switch the driving direction of the rear wheels 16 between forward, neutral, and reverse, change the speed, and change the degree of inclination of the front wheels 14, in other words, the amount of cutting depth of the cutter blade 22 into the material to be cut, and the operation of the power transmission device 26, motor 24, etc. is controlled according to the input content to this operation panel.

[0022] When receiving power from an external power source, a cable for that power is connected to connector 28. As described above, if motor 24 is a three-phase AC motor, a cable for receiving three-phase 200V AC, for example, is connected to connector 28.

[0023] The power conversion device 30 converts the power supplied from an external power source through the connector 28 to a desired voltage and frequency and supplies it to the motor 24. This desired voltage and frequency are the voltage and frequency required for the motor 24 to generate an output suitable for the cutter blade 22 to perform cutting. Preset values ​​may be used, or the values ​​may be changed in response to an instruction from an operator to increase or decrease the rotation speed of the cutter blade 22 during cutting work. The power conversion device 30 includes an inverter that uses, for example, a fast recovery diode (FRD), which is a diode with a short reverse recovery time (trr). This allows the inverter to operate at high speed.

[0024] The cutter wheel 10 is also provided with a hand crank 42. The rotation shaft of the hand crank 42 is connected to the input shaft of the manual drive unit 40, and when the operator of the cutter wheel 10 rotates the hand crank 42, the rotation of the hand crank 42 is input to the manual drive unit 40.

[0025] The manual drive unit 40 includes a gearbox and the like, and the rotation of the input shaft is changed in speed at a predetermined gear ratio and transmitted to the output shaft. In this embodiment, the output shaft of the manual drive unit 40 is connected to the output shaft of the power transmission unit 26 so that power can be transmitted. Therefore, by rotating the hand crank 42, the rear wheels 16, which are the drive wheels, can be rotated, and the cutter vehicle 10 can be manually moved forward or backward.

[0026] The cutter vehicle 10 also has an operating handle 44. The operating handle is attached to the side of the cutter vehicle 10, and by the operator pushing or pulling the operating handle 44, the cutter vehicle 10 can be moved manually even when no driving force is being generated from the electric motor 24, in other words, when no external power is being supplied or when the power transmission device 26 is in a neutral state even during cutting operations by the electric motor 24. The operating handle 44 is provided to be extendable, for example, and can be adjusted to a length that is easy to use depending on whether the cutter vehicle 10 is being pushed or pulled, or whether the front wheels 14 are being deployed or retracted by the lifting arm 18.

[0027] The cutter vehicle 10 in this embodiment is a so-called dry concrete cutter that cuts concrete without supplying liquid such as water to the cutting area. The cutter vehicle 10 is equipped with a dust collector 50, a blower 48, and a blower motor 46. The blower motor 46 is driven by power from the power converter 30 described above or a battery 34 described below. A fan (not shown) of the blower 48 is connected to the blower motor 46, and when the fan is rotated by the blower motor 48, the blower 48 draws air through its suction port and discharges it through an exhaust port 54. The suction port of the blower 48 is connected to a dust collector 50. The suction port 52 of the dust collector 50 is provided near the cutter blade 22 and draws in air containing dust generated during cutting by the cutter blade 22. The dust collector 50 is provided with a filter or the like inside, and separates and accumulates dust contained in the air sucked in from the suction port 52 inside the dust collector 50, and discharges the air from which the dust has been removed from the exhaust port 54 through the blower 48.

[0028] In the cutter vehicle 10 having such a configuration, the rear wheels 16 for moving the cutter vehicle 10 are driven by the driving force of the motor 24, and therefore can only be used when an external power source is supplied to the cutter vehicle 10. Therefore, while the cutter vehicle 10 can be moved while cutting is being performed with the cutter blade 22, it cannot generate driving force when no external power source is supplied. Therefore, for example, when the cutter vehicle 10 is being transported between cutting locations, external power is not supplied, and the cutter vehicle 10 must be moved using the handle 42 or pushed via the operating handle 44, which poses safety and burdens on the worker.

[0029] To address this issue, the cutting vehicle 10 of this embodiment is configured to include, in addition to the above-mentioned components, a battery 34, a DC-AC inverter (hereinafter simply referred to as the inverter) 36, a conversion device 38, a switching device 32, a charging circuit 56, etc.

[0030] The battery 34 is a rechargeable secondary battery such as a lead storage battery, and generates a direct current at a predetermined voltage.

[0031] The inverter 36 converts the direct current supplied from the battery 34 into three-phase alternating current suitable for driving the motor 24 .

[0032] The converter 38 converts the three-phase AC current generated by the inverter 36 to a frequency suitable for driving the motor 24. Like the converter 30 described above, the converter 38 also includes an inverter using fast recovery diodes (FRDs). This allows the inverter to operate at high speed. The converter 30 described above is used for the output of the motor 24 when driving the cutter blade 22 or, in addition, when driving the cutter wheel 10 via the rear wheels 16, while the converter 38 is used for the output of the motor 24 when only driving the cutter wheel 10 via the rear wheels 16. Therefore, the converter 38 can have a lower capacity than the converter 30.

[0033] The switching device 32 switches the current supplied to the motor 24 between the AC current generated by the converter 30 and the AC current generated by the converter 38. The switching device 32 may perform the switching based on the operation of the operator of the cutter vehicle 10. Alternatively, the switching device 32 may perform the switching automatically so that the AC current generated by the converter 30 is supplied to the motor 24 when power is supplied from an external power source via the connector 28, and so that the AC current generated by the converter 38 is supplied to the motor 24 when power from the external power source via the connector 28 is interrupted.

[0034] The cutting wheel 10 also has a charging circuit 56. When power is supplied to the cutting wheel 10 from an external power source via the connector 28, the charging circuit 56 converts a portion of the power supplied from the external power source into direct current, which can then be used to charge the battery 34.

[0035] The cutter vehicle 10 of this embodiment includes a cutter blade 22, an electric motor 24 for driving the cutter blade 22, a chassis 12 that houses the cutter blade 22 and the electric motor 24, a plurality of front and rear wheels 14 and 16 that rotatably support the chassis 12, and a power transmission device 26 that transmits the output of the electric motor 24 to the plurality of rear wheels 16, which are drive wheels. The electric motor 24 can be operated by either power supplied from an external power source (first power supply means) via a connector 28 or power supplied from a battery 34 (second power supply means) different from the first power supply means. This allows the electric motor 24 to be operated by either power supplied from a plurality of different power supplies. This allows the motor for driving the cutter vehicle 10 to also drive the cutter blade 22, eliminating the need for a separate motor for moving the cutter vehicle 10 in addition to the motor 24 for driving the cutter blade 22.

[0036] Furthermore, according to the cutting wheel 10 of this embodiment, since the battery 34 is provided as the second power supply means, the power supply means can be included inside the cutting wheel 10.

[0037] Furthermore, according to the cutter vehicle 10 of this embodiment, when power is not being supplied from an external power source, the electric motor 24 is driven by power from the battery 34, so that the external power source can be used with priority over the battery 34.

[0038] Furthermore, according to the cutter vehicle 10 of this embodiment, the electric motor is driven by the second power supply means when cutting by the cutter blade is not being performed. As a result, the electric motor is driven by the battery 34, which is the second power supply means, when the load on the electric motor is small.

[0039] Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can also be applied to other embodiments.

[0040] In the above-described embodiment, the blower 48 is driven by the motor 46, but this is not limiting and the blower 48 may be driven by rotation transmitted from the output shaft of the drive motor 24 for the cutter blade 22 via a belt (not shown). In this case, the number of electrical components can be reduced, which makes maintenance easier and also reduces the weight of the cutter car 10.

[0041] In the above embodiment, the dust collector 50 is of a filter type, but the present invention is not limited to this, and a cyclone type may also be used.

[0042] Furthermore, while the above-described embodiment uses a dry-type cutter vehicle 10, this is not limiting. Specifically, a wet-type cutter vehicle may also be used. Such a wet-type cutter vehicle 10 includes a water supply tank, a collection tank, a sprayer, a suction device, etc., and the sprayer sprays water stored in the water supply tank near the contact point between the cutter blade 22 and the concrete to be cut, and the suction device collects water mixed with powdered concrete fragments generated by the cutting and temporarily stores it in the collection tank. In this case, it is not necessary to provide the dust collector 50, blower 48, and blower motor 46 of the cutter vehicle 10 of the above-described embodiment.

[0043] Furthermore, in the above-described embodiment, an HST is used as the power transmission device 26, but the present invention is not limited to this. Instead of an HST, for example, a drive motor may be provided, and the drive motor may be used to drive (move) the cutting car 10 with power from the battery 34. In such a case, a power supply circuit for the drive motor is provided, and power from the battery 34 is supplied to the drive motor via the DC-AC inverter 36 and the power supply circuit. However, since the electric motor 24 is not used to move the cutting car 10 when no external power source is supplied, the conversion device 38 and switching device 32 are not required.

[0044] It should be noted that the above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0045] 10: Electric concrete cutter 12: Body 14: Front wheel (wheel) 16: Rear wheel (wheel) 22: Cutter blade 24: Motor 26: Power transmission device 28: Connector 30: Conversion device 32: Switching device 34: Battery 36: DC-AC inverter 38:Conversion device

Claims

1. An electric concrete cutter having a cutter blade, an electric motor for driving the cutter blade, a vehicle body that houses the cutter blade and the electric motor, a plurality of wheels that rotatably support the vehicle body, and a power transmission device that transmits the output of the electric motor to some of the plurality of wheels, the electric motor is operable by either power supplied from a first power supply means or power supplied from a second power supply means different from the first power supply means; An electric concrete cutter characterized by:

2. The second power supply means has a battery; 2. The electric concrete cutter according to claim 1,

3. the first power supply means is an external power source, and when power is not being supplied from the first power supply means, the electric motor is driven by power from the second power supply means; 3. The electric concrete cutter according to claim 2,

4. the second power supply means drives the electric motor when cutting by the cutter blade is not being performed; 4. The electric concrete cutter according to claim 3,

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